Pull-back spring for scraper tail gates



May 31, 1938. R; G. LE TOURNEAL! 2,119,335

PULL-BACK SPRING FOR SCRAPER TAIL GATES Filed Jan. 16, 1957 2 She ets-Sheet 1 INVEINTOR R. 6. Le7bumeau @w ?=.m.m:

ATTORNEY I May 3 1938. R. G. LE TOURNEAU PULL-BACK SPRING FOR SCRAPER TAIL GATES Filed Jan. 16, 1957 2 Sheets-Sheet 2 INVENTOR R. G.Le7'ourneau BY @QQmm ATTORNEY,

Patented may 3i, 193% main Robert 6:. Le Tourncau,

It. G. he Tourneau, Ina,

orricr.

lornia Application llanuary 1d, 1937,

d Glaims.

This invention relates .to scrapers of the type shown in my Patent No. 2,112,105, particularly with respect to the return or pull-back means for the tail gate of the scraper.

In the previous scraper, the

tail gate was returned by a series of compression springs which were mounted in spring boxes, one on the frame and the other on the tail gate, and which springs were compressed by the advancing of the tail gate. With this compression-of the springs was springs to have the necessary arrangement, a great travel and required for the pulling strength when the tail gate approached a fully retracted position. This consumed considerable power and necessitated the use of a very heavy structure to resist the springs when they were greatly compressed.

thus

power of the spring needed and less tractor power power control unit) is required spring.

A further object is to provide for the purpose which is available when it is most (applied to the an arrangement utilizes a chain spring of considerably lesser length than was originally required, thus simplifying ducing the cost the apparatus and reof construction.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal specification and claims.

of the following.

I In the drawings similar characters of reference indicate corresponding parts in the several views:

Fig. Us a side section showing my construction.

Fig. 2 is a section showing the tail Fig. 3 is a fragmentary rear scraper.

Referring now more acters of reference on as a whole is substantially co-pending application and nal frame beams with, a rear bowl a tail gate t slidably mounted and movable lengthwise in the tail gate is pulled forwardly by same manner as the elevation oi a scraper partly in improved tail gate retracting fragmentary enlarged longitudinal gate pull-bash structure.

end view of the particularly to the charthe drawings, the scraper same as in said comprises longitudil, a front bowl 2 rigid there- 3 slidable in the front bowl, and

on the beams i rear bowl. The a cable b in the in the previous structure.

Wheels 6 are disposed rearwardly of the tail gate, the axles l of said wheel being supported to tension the Peoria, m... assignor to a corporation oi. Cali- Serial No. 120,951

(ill. 37-426) at their outer ends on bearings mounted on the lower frame beams l, and at their inner ends in bearings t mounted on a central rearwardly projecting beam 9. I

A cross-beam ill supported at its ends from the beams i is disposed above the wheels and is also connected to and braced from the beam 9 by vertical transverse diagonals H and by downwardly and rearwardly sloping and transversely converging diagonals lie.

A rigid compression beam l2, preferably of cylindrical form, ly from the cross beam Ill centrally thereof to a connection with the top of the A frame it. which projects upwardly from the beams l at the front and to which the cable actuated pusher beam it is connected, as before. By reason of the above described construction, it will be seen that a rearward pushing movement on the beam M is transmitted to the beam l2 and thence to the beam 9 rearwardly of the wheel axle, imparting the desired lifting effect to thescraper as a whole, as in the previous device.

The beam i2 is hollow and its rear portion contains a longitudinal extending helical spring IS. The upper forward end of this spring is engaged by a cap it to which one end of a cable it is secured. This cable extends through the spring and across the beam it and is thence wound over a drum it. This drum is disposed between and turnahly supported from the diagonals lie, the upper face of the drum being tangent to the axis of the spring.

Another cable it is connected to the back of the tail gate t and extends rearwardly and about a drum 2t from underneath. This drum is formed as a unit with the drum it to one side of the same and is arranged in the shape oi" a spiral cable receiving face or groove. as shown. The cable it, when the tail gate is retracted, is wrapped about the spiral .groove for substantially the full length thereof and pays out from the small end or the drum, as shown in Fig. 2. in this position of the parts, the spring it is extended and substantially slack.

When the tail gate is pulled forwardly by the cable it, the cable it is unwound from the drum it, while the cable it winds onto the drum it, thus placing the spring it under compression.

. The initial compression of the spring, when but little power is necessary to effect this, is practically in direct proportionto the movement of the tail gate, since the drum it is practically the same size as the small or inner portion of the spiral groove of the drum it. The compressing extends forwardly and upwardlid l the drum 20 with its being substantially fully extended movement of the springs becomes increasingly slow with a constant speed of movement of the tail gate as the cable I!) gradually unwraps from ever increasing size. The leverage thus imparted to the spring compressing cable enables the spring to be placed under a great tension with a minimum of power. Also, a relatively great tail gate movement, such as is necessary in a scraper of this type, is translated into a much shorter spring compressing movement and a shorter spring may therefore be used to give the same effect obtained with the previous device.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be restorted to as do not form a v departure from the spirit of the. invention, as defined by the appended claims.

Having thus described my invention, what I claim as new and useful and desire to secure by Letters Patent is:

1. A tail gate pull-back spring motor for an earth working scraper having a bowl, a tail gate movable lengthwise of the bowl and means to pull the tail gate forwardly; said spring motor comprising a compressible helical spring mounted on the scraper, one end of the spring being fixed against movement and said spring When the tail gate is in a fully retracted position, a cable drum turnably mounted on the scraper beyond the fixed end of the spring, a. cable wound on said drum and extending through the spring and ap plied to the other end thereof, another cable drum mounted as a unit with the first named drum, said other drum comprising. a spiral cable receiving groove, the smallest radius of the spiral being approximately the same as that of the first named drum, and another cable wound on said groove and anchored at the large end or the spiral, said other cable being connected to the back of the tail gate and paying out from the small end of the spiral when the tail gate is recable being arranged is unwound from its drum with the advancing movement of the tail gate.

2. A tail gate pull-back spring motor for an earth working scraper having a bowl, a tail gate movable lengthwise of the bowl and means to pull the tail gate forwardly; said spring motor comprising a drum unit mounted on the scraper, said unit having one drum of constant diameter and another drum having a spiral cable receiving groove, said drums being secured against relative rotation, cables secured at one end to the drums for winding thereabout in opposed directions, the cable for said other drum being secured thereto at the large end of the spiral groove, a normally expanded helical compression spring mounted on the scraper with one end fixed against movement, the cable from said one drum normally being unwound and passing through the spring from the fixed end andsecured to the'other-end thereof, and the cable from said other drum being oporatively connected to the tail gate and arranged to be wound onto the spiral groove when the tail gate is in its normal and retracted position.

3. A spring motor comprising a drum unit having one drum of constant diameter and another drum formed with a spiral cable receiving groove, cables secured to the drums for winding thereabout in opposed directions, a helical compression spring mounted substantially tangent to said one drum and fixed against movement at the end adjacent the drum, the cable from said drum passing through the spring from the fixed end thereof and secured to the other end of said spring; and means to mount the spring motor on a scraper having an independently advanced tail gate so that the cable from the other drum may be operatively connected to the tail gate in a direction to cause the spring to be placed under tension by the advancing movement of the tail gate whereby said tail gate will be retracted when the adva cing pressure on the tail gate is released.

4. A structure as inclaim 1, in which the scraper includes a frame having a rigid hollow compression beam extending substantially tangent to the-first named drum; the helical spring being disposed within the beam.

ROBERT G. LE TOURNEAU. 

